[Rd] R Installation Manual - ATLAS BLAS guidance that is not in the current version

[Prof Brian Ripley]

On 09/05/2012 19:54, Adler, Avraham wrote:
> Good afternoon.
>
> I am trying to compile a version of Rblas.dll based on ATLAS for the
Corei7. I had remembered that there was mention of which file to adjust
and that "xerbla" needed to be removed from one of the outputs from the
last time I tried a few years ago. The most recent version of the R
Installation manual does not say anything about this. An older version
(2.10 I believe) has the following text:
>
>        Optionally, you can install a version of ATLAS
>        (`math-atlas.sourceforge.net'
>        (http://math-atlas.sourceforge.net/)) tuned to your system for
>        fast linear algebra routines. Pre-built `Rblas.dll' for various
>        Pentium and AthlonXP chips are available in the
>        `windows/contrib/ATLAS' area on CRAN.  If you are building R from
>        source, there are macros `USE_ATLAS' and `ATLAS_PATH' in the file
>        `MkRules'.  Set `USE_ATLAS = YES' and `ATLAS_PATH' to where the
>        ATLAS libraries are located.  You will need to make the libraries
>        yourself(1): none of the binaries we have seen are compiled for
>        the correct compiler.  Since R has its own `xerbla' it is best to
>        delete that in ATLAS by
>
>             ar d /path/to/libf77blas.a xerbla.o
>
> Would it be possible to restore the above information to the next version of the manual for future reference, please?

No, as this is no longer supported (and various attempts to make it work 
have failed with incorrect results/segfaults).

We do support the use of the legacy Goto BLAS these days (64-bit only, 
but anyone who cares about performance will be using 64-bit).

As you have found in another thread, avoid over-optimizing code: the 
risk of incorrect answers is serious and the performance gains small.

> Thank you,
>
> Avraham Adler
> ______________________________________________
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> https://stat.ethz.ch/mailman/listinfo/r-devel


-- 
Brian D. Ripley,                  ripley at stats.ox.ac.uk
Professor of Applied Statistics,  http://www.stats.ox.ac.uk/~ripley/
University of Oxford,             Tel:  +44 1865 272861 (self)
1 South Parks Road,                     +44 1865 272866 (PA)
Oxford OX1 3TG, UK                Fax:  +44 1865 272595